Clathrates are substances in which a lattice structure made up of first molecular components (host molecules) that trap or encage one or more other molecular components (guest molecules) in what resembles a crystal-like structure. In the field of hydrocarbon exploration and development, clathrates of interest are generally clathrates in which hydrocarbon gases are the guest molecules in a water molecule host lattice. They can be found in relatively low temperature and high pressure environments, including, for example, deepwater sediments and permafrost areas. Clathrates are also referred to as hydrates, gas hydrates, methane hydrates, natural gas hydrates, CO2 hydrates and the like. For the purposes of this invention the term Clathrates will be used.
Clathrates generally form a significant portion of the structural support for the reservoir in which they occur, particularly with respect to cementing and/or occupying pore space. As clathrates dissociate, the constituents become mobile and cease acting as support, weakening the formation and potentially causing localized compaction of the reservoir. In a production environment, such localized subsurface compaction can lead to effects on equipment in the local area, both subsurface and on the surface. For example, in the subsurface environment, casings and drill strings may be collapsed due to high compressive loading caused by compaction of the reservoir, subsidence of the reservoir overburden strata and uplift of the reservoir underlying strata. On the surface, subsidence caused by subsurface clathrate dissociation and reservoir compaction can lead to sinkholes, subsidence, and other related motions that can cause damage to surface equipment such as well-heads, pipelines, equipment and other facilities in the immediate vicinity. The inventors have recognized a need to reduce or remediate this possibility.